feature: make gho -> stkgho route reversible

[NandyBa]

Hello, currently you have a working gho -> stkgho adapter. This adapter use stake function and a rate of 1:1.
Could be possible for you to add the reverse route so stkgho -> gho so trade can be done on both directions ?

To perform the stkgho -> gho exchange the function to call is cooldown and redeem. Rate is also 1:1
Notice:

• that previously the rate could be affected by slashing. Yet this is not the case anymore.
• cooldown have been updated to 0 so now both cooldownand redeem can be done on the same tx (cf screenshot bellow)